package me.arraylist.demo.Student;

import java.util.ArrayList;
import java.util.Random;
import java.util.Scanner;


public class App {
    public static void main(String[] args) {
     loop:   while (true) {
            ArrayList<User> list = new ArrayList<>();
            System.out.println("欢迎来到学生管理系统");
            System.out.println("请选择操作 1登录 2注册 3忘记密码 4退出");
            Scanner sc = new Scanner(System.in);
            int choice = sc.nextInt();
            switch (choice) {
                case 1 -> login(list);
                case 2 -> register(list);
                case 3 -> forgetPassword(list);
                case 4 -> {
                    System.out.println("退出");
                    break loop;
                }
                default -> System.out.println("您的输入有误");
            }
        }
    }

    private static void login(ArrayList<User> list) {
        Scanner sc=new Scanner(System.in);
        System.out.println("请输入用户名");
        String username=sc.next();
        boolean falg=contains(list,username);
        if(!falg){
            System.out.println("用户未注册,请先注册");
            return;
        }
        System.out.println("请输入密码");
        String password=sc.next();
        while (true) {
            String rightCode=getCode();
            System.out.println("正确的验证码为"+rightCode);
            System.out.println("请输入验证码");
            String code=sc.next();
            if(rightCode.equals(code)){
                 System.out.println("验证码正确");
                 break;
             }
             else{
                 System.out.println("验证码错误");
             }
        }

    }

    private static String getCode() {
        ArrayList<Character> list=new ArrayList<>();
        for (int i = 0; i < 26; i++) {
            list.add((char)('a'+i));
            list.add((char)('A'+i));
        }
        Random random=new Random();
        StringBuilder sb=new StringBuilder();
        for (int i = 0; i < 4; i++) {
            int index=random.nextInt(list.size());
            sb.append(list.get(index));
        }
        int number=random.nextInt(10);
        sb.append(number);
        char[] arr=sb.toString().toCharArray();
        int index1=random.nextInt(arr.length);
        int index2=random.nextInt(arr.length);
        char temp=arr[index1];
        arr[index1]=arr[index2];
        arr[index2]=temp;
        return new String(arr);
    }

    private static void register(ArrayList<User> list) {
        Scanner sc = new Scanner(System.in);
        String username;
        String password;
        String ID;
        String phone;
        while (true) {
            System.out.println("请输入用户名");
            username = sc.next();
            boolean flag1 = checkUsername (username);
            if (!flag1) {
                System.out.println("用户名格式错误");
                continue;
            }
            boolean flag2=contains(list,username);
            if(flag2){
                System.out.println("用户名已存在,请重新输入");
            }
            else{
                System.out.println("用户名格式正确");
                break;
            }
        }
        while (true) {
            System.out.println("请输入密码");
            password = sc.next();
            System.out.println("请再次输入密码");
            String again = sc.next();
            if(!password.equals(again)){
                System.out.println("两次密码不一致");
                continue;
            }
            else{
                System.out.println("密码可用");
                break;
            }
        }
        while (true) {
            System.out.println("请输入身份证号");
            ID=sc.next();
            boolean flag3=checkID(ID);
            if(flag3){
                System.out.println("身份证号可用");
                break;
            }
            else{
                System.out.println("身份证号格式错误");
            }
        }
        while (true) {
            System.out.println("请输入手机号");
            phone=sc.next();
            boolean flag4=checkPhone(phone);
            if(flag4){
                System.out.println("手机号可用");
                break;
            }
            else{
                System.out.println("手机号格式错误");
            }
        }
        User u=new User(username,password,ID,phone);
        list.add(u);
        System.out.println("注册成功");
    }

    private static void forgetPassword(ArrayList<User> list) {

    }
    private static boolean checkUsername(String username) {
        if(username.length()<3||username.length()>10){
            System.out.println("用户名长度必须在3-10位之间");
            return false;
        }
        int count=0;
        for (int i = 0; i < username.length(); i++) {
            char c=username.charAt(i);
            if(c>='a'&&c<='z'||c>='A'&&c<='Z'){
                count++;
               break;
            }
        }
        return count>0;
    }

    private static boolean contains(ArrayList<User> list, String username) {
        for (int i = 0; i < list.size(); i++) {
            User u = list.get(i);
            if (u.getUsername().equals(username)) {
                return true;
            }
        }
        return false;
    }

    private static boolean checkID(String ID){
        if(ID.length()!=18){
            System.out.println("身份证长度错误");
            return false;
        }
        if(ID.startsWith("0")){
            System.out.println("身份证不能以0开头");
            return false;
        }
        for (int i = 0; i < ID.length()-1; i++) {
            char c=ID.charAt(i);
            if(!(c>='0'&&c<='9')){
                System.out.println("身份证必须是数字");
                return false;
            }
        }
        char c=ID.charAt(17);
        if(!(c=='X'||c=='x'||(c>='0'&&c<='9'))){
            System.out.println("身份证最后一位必须是X,x或数字");
            return false;
        }
        return true;
    }

    private static boolean checkPhone(String phone){
        if(phone.length()!=11){
            System.out.println("手机号长度错误");
            return false;
        }
        if(phone.startsWith("0")){
            System.out.println("手机号不能以0开头");
            return false;
        }
        for (int i = 0; i < phone.length(); i++) {
            char c=phone.charAt(i);
            if(!(c>='0'&&c<='9')){
                System.out.println("手机号必须是数字");
                return false;
            }
        }
        return true;
    }
}
